Electrical connector



y 7, 1954 D. A. MARQUIS 3,140,142

ELECTRICAL CONNECTOR Filed Nov. 7, 1961 INVENTOR DONALD A. MARQUIS BY 2% 27 United States Patent "cc 3,140,142 ELECTRICAL CONNECTOR Donald A. Marquis, West Hurley, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Nov. 7, 1961, Ser. No. 150,705 1 Claim. (Cl. 33927'6) The present invention is directed to an electrical connector of the type which is to beplaced in mechanical and electrical engagement with a conductor by crimping operations, where the crimping operations are carried out on outward-facing surface areas of the connector subsequent to the introduction of a portion of the conductor through an opening of the connector to a point adjacent the crimping operation areas.

In the past, electrical connectors of this type have been used in which the location of multiple crimped portions with respect to each other has been suchas to allow flexing of both the connector along the crimped portion and the wire contained therein when stress is placed on the connector, for instance, by movement of the part of the conductor which extends outwardly from the connector. In general, such flexing is considered harmful because it interferes with the usefulness of the connector by loosening the mechanical bond between connector and conductor and by allowing variation in the electrical resistance of the joint between connector and conductor. Further, in working an inexpensive connector having tubular, metallic ferrule portion which receives the conductor where the ferrule is formed from sheet stock with the free ends of the stock formed into an unsealed, butt joint, it is necessary in traditional crimped connectors to specially orient crimped portionsrof the ferrule with respect to the seam or slit of the butt joint in order to avoid poor mechanical and electrical connections between connector and conductor which may be endangered by buckling or heaving of metal adjacent the seam of the ferrule in the process of crimping.

Accordingly, it is an object of the present invention to provide a new and improved crimped connector to be mechanically and electrically joined to a conductor.

Another object of the present invention is to provide a connector of the above-described type in which the electrical resistance between connector and conductor is held at a minimum value.

Another object is to provide a connector of the abovementioned type which, when joined to a conductor, has stable mechanical and electrical characteristics in the face of stresses placed on the crimped portion of the connector.

Another object is to provide a connector having the above attributes and in which the crimped portion of the connector is a ferrule having unsealed seam where the quality of the electrical and mechanical bond between the connector and the conductor crimped thereto is substantially independent of the orientation of the seam with respect to the crimped areas of the ferrule.

The foregoing and other objects, features and advantages of the invention will be apparent from the description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

FIG. 1 shows a side View of a portion of an uncrimped electrical connector and a conductor for insertion therein.

FIG. 2 shows a side view partially cut away of the crimped connector and conductor of FIG. 1.

FIG. 3 shows a section taken through 33 of FIG. 2 and FIG. 4 shows a plan view of the crimped connector and conductor of FIG. 2.

Referring to the drawings, FIG. 1 shows a part of a 3,140,142 Patented July 7, 1 964 connector having a metallic ferrule 1 and a rearwardly extending flange 2 which is integral with ferrule 1. Both ferrule 1 and flange 2 originally are of substantially circular cross-section and may have an unsealed, butt seam A extending along the length thereof. As indicated in FIG. 1, a bared conductor 3 is furnished for introduction within the opening of ferrule 1 and flange 2 with the conductor oriented to extend in a direction indicated by the arrow shown in FIG. 1, which is substantially parallel to the principal axis of ferrule 1. While conductor 3 is shown as being multistrand, it is to be understood that the conductor could be a single, solid wire and yet cooperate with the hereinafter described apparatus of the connector.

With conductor 3 positioned within ferrule 1 as indicated in FIG. 2, a portion of the surface of ferrule 1 lying between points 5 and -6 is crimped inwardly with respect to the principal axis of ferrule 1. This crimp is a boat-shaped indentation which extends along the length of ferrule 1 and is symmetrical about a theoretical plane which, with reference to FIG. 4, extends normally from the paper on which the drawing is shown and in a direction which is substantially parallel to or includes the principal axis of ferrule 1, so that the boat-shape crimp forms a corrugationimpressed in and extending lengthwise along a part of the length of ferrule 1 between points 5 and 6.

As indicated in the drawings, this crimped portion has a smooth, concave portion 7 forming the bottom of the boat and is bounded by inwardly slanted ends 8. The crimping operation referred to above is effected in such a manner that the metal of ferrule 1 cold flows into the above-described shape, with the result that the crimped portion has the mechanical strength and is attached to the remainder of ferrule 1 with tenacity which approaches the properties of the same mass of metal before the crimping operation was effected. It is pointed out that by virtue of the cold flow of metal in the crimping operation into the above-described shape, the orientation of slit A drawing with respect to the crimp is unimportant, because a slit in the metal included in the crimp is distorted in such a manner that the final shape of the ferrule portion including the crimp is identical without regard to the pres ence or absence of the slit within the mass of metal distorted. The purpose of this boat-shape crimp is: with its inwardly facing surface to crush down and compact conductor 3 into mechanical and electrical engagement with ferrule 1; and by virtue of its regular, corrugated shape and the orientation of that shape with respect to the principal axis of ferrule 1, to give the crimped portion of ferrule 1 resistance to flexing along its length which approaches maximum value in those directions which are coincident with the above-described plane about which the crimp is symmetrical.

At least one additional crimp 9 is placed in ferrule 1 in orientation to be described. As indicated in the drawing, the number of these additional crimps 9 and 10 in the preferred embodiment of the present invention is two. It is the purpose of the additional crimp or crimps in combination with the above-described boat-shape crimp to make ferrule 1 and conductor 3 further resistive to flexing and to further assist in mechanically securing conductor 3 to ferrule 1. It is to be realized that such additional crimps may be created coincidently or serially in time with respect to the creation of the above-described boat-shaped crimp in ferrule 1.

Each of above-mentioned additional crimps 9 and 10 in the surface of ferrule 1 forms a regular, impressed corrugation, such corrugation being oriented to lie in ferrule 1 between points 5 and 6, i.e., along the same length of ferrule 1 in which the boat-shape crimp is impressed. The principal axis of the corrugation in each additional crimp lies in a direction substantially normal to the principal axis of ferrule 1 and to the axis of symmetry of the boat-shape crimp, and, further, is symmetrical about a theoretical plane normal to the ferrule principal axis and to the plane of symmetry to the boat-shape crimp. As indicated in FIG. 2, it is preferred that the additional crimps 9 and be oriented to center on points in the surface of ferrule 1 which are substantially opposite to the indentation of the boat-shape crimp. As in the case of the boat-shape crimp, each additional crimp is formed in a cold flow operation with the above-mentioned advantages that grow out of using a cold flow distortion of the metal. From the cut-away portion of FIG. 2, it is to be seen that each of the additional crimps 9 and 10 further compresses the inward facing surface of ferrule 1 into engagement with conductor 3 and therewith causes conductor 3 to be distorted to substantially fill the interior of the crimped length of ferrule 1. It is to be seen that the reduced cross-sectional area of ferrule 1 and the resulting distortion and reduction of cross-sectional area of conductor 3 at each of additional crimps 9 and 10 raises the mechanical resistance of the connector to withdrawal of conductor 3 along its own length from ferrule 1. Further, it is to be seen that by orienting the boat-shape crimp and each of additional crimps 9 and 10 corrugations to be symmetrical with respect to planes which are substantially normal to each other and with one such plane oriented to be normal to the principal axis of ferrule 1, the crimped part of ferrule 1 and the length of conductor 3 lying therein is made resistive to flexing along the length of the crimped portion in any direction that also is normal to the principal axis of ferrule 1.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

In a device to be electrically and mechanically joined to a conductor Where said device has a tubular, metallic ferrule with an opening along the principal axis thereof for receiving said conductor,

an unsealed butt seam extending along the longitudinal direction of said ferrule,

a first boat-shaped crimp in the surface of said ferrule parallelly disposed adjacent the principal axis of said ferrule and forming an impressed corrugation indenting said conductor,

said first crimp being oriented independent of the position of said seam and effective for compacting said ferrule into electrical and mechanical connection with said conductor,

a plurality of substantially identical elongated second crimps in the surface of said ferrule transversely disposed adjacent the principal axis of said ferrule at points along the length of said ferrule which include said first crimp and which are substantially opposite to said first crimp,

each of said second crimps forming an impressed corrugation indenting said conductor for further compacting said ferrule into mechanical and electrical connection with said conductor and being effective in combination with said first crimp for making said ferrule resistive to flexing in any direction normal to the axis of said ferrule.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,074 Buchanan Oct. 18, 1955 557,037 Toquet Mar. 24, 1896 1,987,489 Mucher Jan. 8, 1935 2,109,837 Davis Mar. 1, 1938 2,674,725 Buchanan Apr. 6, 1954 2,685,076 Hoffman July 27, 1954 2,816,276 Fuller et al. Dec. 10, 1957 2,906,017 Badeau Sept. 29, 1959 FOREIGN PATENTS 214,123 Australia Apr. 3, 1958 

